Welcome to another MedCram COVID-19 update. Just when we thought things were getting better, here
at least in the United States, the delta variant has popped up and that's what we're going to talk
about. But even more importantly, let's talk about variants in general. So if you've got a coronavirus
and specifically the SARS-CoV-2 virus and it goes to infect an individual, the issue is as we've
talked about before the virus is going to hijack your cells to produce many more copies of itself.
In fact, in some studies it's been shown that the virus will make up to a billion copies of itself
in just one individual, but here's the problem: the way that it does it is not very accurate and so
there will be some slight mistakes, and you might see a variant being produced in these infections.
Now, variants are produced all the time; in fact, the truth is is that most of these variants are just
duds. They don't infect anything or they might not affect as well, but every now and then you
might get a mutation that allows the virus to bind better to the next individual, and that would be a
variant of concern which are not very common. We have some examples we have the UK variant, for
instance, or the South African variant. And more recently, we have the delta variant, which we're
going to talk about now. This was first discovered in India; this should not be very surprising, as
you may recall at one point in India they were getting as many as 400,000 cases on a daily basis.
Now imagine those 400,000 cases each producing over a billion copies, and you can see there that
it's only a matter of time before you get a mutation that is fortuitous for the virus,
and you can see here very easily that a mutation that allows the virus to infect better and be
more contagious is going to be a virus that is certainly going to take over the world. In terms
of the different types of variants, so while there may be many different variants at once if there is
a variant that is able to infect better. And that's really all that matters to the virus,
is to spread its genetic material as far and wide as it possibly can. That is the virus
variant that is going to win in terms of the prevalence in the population, and
again this mutation that causes increased fitness can be manifested as better binding
or evading the immune system. There's a number of different ways that this can happen,
so as it turns out, this delta variant has some characteristics of it and it's known as
B.1.617.2. It seems that it is more contagious than the original virus
to give you an example. Some experts have said that if you look at the original virus,
the number of people that one person would have infected otherwise, known as the R-naught (R0),
it was originally around 2.5. This delta variant has been estimated anywhere between 3.5 and 4.0.
Okay, so it seems to be more contagious, but where does it seem to be found the most?
Well, there was another paper that was published. This paper was known as the "REACT-1
round 12 report," and while it has not been published or peer-reviewed as yet, there are
some interesting findings. This was put out by the Imperial College in London in the United Kingdom,
and what they found is that the prevalence of the delta variant in those aged 5 to 49, in other words,
those people less than 50 years of age, was two and a half times higher compared to those that were
age 50 years and above. And so while it is possible that people over the age of 50 are more likely to
be vaccinated, there could also be a connection between this virus and younger aged individuals.
All right, what about hospitalization? Well, there was a correspondence that was published
in the Lancet regarding the delta variant, and they were able to look at PCR, and what they found was
surprising. What they found, essentially using a Cox regression analysis, which is a way of
adjusting for age, sex, and economic status, temporal trend comorbidities, was that the delta variant had
a 1.85 times higher risk of getting the person infected in the hospital with severe COVID-19.
So if you look at the SARS-CoV-2 infection since April in the United States, you'll see here that
the British variant, or the UK variant, the B.117, has been up to this point the most dominant infection.
But as of recently, there is one that is taking over very quickly, and that is the delta variant.
And as you can see, the delta variant has made some inroads very quickly here in the last two to three
months. And the reason for that is because it is the most infectious variant that is currently
there in the UK, where greater than ninety percent of the cases are the delta variant. It is what is
fueling the latest surge. At least 60 percent of the population is vaccinated with two doses, which
is actually very good, and despite the fact that the cases have gone up in England and in Wales,
Scotland and Northern Ireland, the good news is that the corresponding deaths have not come along
with that surge as yet. In Israel, where they've done a tremendous job of vaccinating, primarily
with the very effective Pfizer-BioNTech vaccine, there has been only a small recurrence of cases,
at this date, most of them from the delta variant. So where we stand here in the United States is
that there has definitely been a resurgence and a doubling of the number of cases, which is an early
sign that there's something potentially coming, and we are seeing here on the daily deaths chart
that for the first time, daily deaths have stopped going down and are now starting to creep up.
In California, and specifically in Southern California, where I practice, there has been a
recent resurgence of cases of SARS-CoV-2. Daily deaths have not yet picked up, but I can tell you
anecdotally, in the hospitals that I work at and in the friends that I have, some of them in LA
County, there has been an increase in the number of admitted cases. For instance, one hospital where I
work at had not seen COVID-19 patients in months, literally, are now admitting patients with COVID-19
and some of them are requiring high levels of oxygen. So given that, what are the tools that we
have? How well equipped are we with the different vaccines that are available against this delta
variant? Let's review the data up to this point. Now we know that there are several different
types of vaccines in the world. We're going to talk about these four mainly, because we have
recent data that shows the efficacy of these vaccines against the delta variant: that is the
Pfizer-BioNTech vaccine, the Moderna vaccine, the Oxford-Astrazeneca vaccine and the Johnson & Johnson
vaccine, and they are different. The Pfizer-BioNTech and Moderna, of course, are messenger RNA vaccines,
and the Oxford-AstraZeneca and the Johnson and Johnson are DNA that use adenovirus as the vector.
And if you have more questions about that, look at our previous MedCram videos on those
particular vaccines for more information about how they work. Now, as you know, these
three first vaccines are first and second shot, and the Johnson & Johnson vaccine is a one-time shot. Now,
there's two different categories that I want to refer you to, and the first category that we're
going to talk about is infection. So infection, what I mean by that is: does the vaccine prevent
the individual from being infected, and therefore prevent them from spreading it onto somebody else?
That has great epidemiological importance in terms of stopping that R-naught (R0) number and preventing
the infection from spreading epidemiologically, And, of course, who wants to get sick? Nobody does.
But there's another important endpoint as well, and that's hospitalization. Does the vaccine prevent
the most serious complications of getting SARS-CoV-2, which is of course COVID-19, hospitalization?
High flow oxygen and ventilation, ARDS, things of that nature, and so those are going to be
two different numbers. So let's talk first of all about the Pfizer-BioNTech vaccine.
Now, I'm going to be referencing a number of articles. Some of them have not been peer-reviewed,
but it is recent data. I will give a link to all of these studies in the description below.
So there was a UK study that showed after the first dose -- so we're talking about usually
two weeks after the first dose -- the Pfizer-BioNTech vaccine, regarding the delta variant, I'm talking
about the delta variant now, specifically was 33 percent effective after the first dose and 88 percent
effective after the second dose at preventing symptomatic infection, and that was the UK study.
Now there was a Canadian study that came up with slightly different numbers
that was 56 percent after the first dose and 87 percent after the second dose. There was an Israeli study
that showed after the second dose, they got 64 percent, and there was a Scottish study that showed 79 percent.
Now all of these are above 50 percent and would have been approved if this were the original virus, so I
think these are all very good numbers. And again, we're talking about infection. Now, remember that
the primary way that your body prevents infection is antibodies, and we know that the mutation
that has caused this variant may be slightly off enough that some people's antibody responses may
not be good enough at preventing infection, but remember that one of the things that helps you
prevent getting worse is T cell activation. When T cells are replicated in the human body, they also
are replicated in a way that is not perfect, so it allows for variance in the T cells, and so if you
have variants in the virus and variants in the T cells, that will sometimes allow for a bit of
change. The T cells can be effective at reducing hospitalizations and taking care of cells that
are already infected, and therefore what we typically find is that the hospitalization
numbers are usually much better. So that same UK study found that after the second dose, there was a
96 percent prevention of hospitalization and death if you got the Pfizer-BioNTech vaccine after the second
dose. And when I say prevent here, I'm talking about efficacy. So, in other words, if there's
a 90 percent plus efficacy, that would be in comparison to a control, or where there's no vaccine, which
would have a zero percent efficacy. There was a Canadian study that looked after the first dose,
there was a 78 percent reduction in hospitalization after the Pfizer-BioNTech vaccination, and that was
the Canadian study. You might be wondering why we don't have data after the second dose. There wasn't
enough data points to make that available in the study so far. There was also an Israeli study
that showed in terms of preventing hospitalization after the second dose that it was 93 percent
effective at preventing hospitalization and death in Israel. So the bottom line here for the Pfizer-
BioNTech vaccine is that, despite the fact that delta is more infectious and causes potentially
more hospitalization, Pfizer is exceptionally good at preventing hospitalization and death from the
delta variant. What about Moderna? Well, there was a Canadian study that showed that after the first
dose, there was a 72 percent reduction, and that was the Canadian study. In that same study, after
the first dose, the Moderna vaccine was 96 percent effective at preventing hospitalization and death. Now the
Oxford-AstraZeneca vaccine, which has been given authorization in the UK. After the first dose, they
found it to be 33 percent effective at preventing infection. And after the second dose, 60 percent
effective. That was the UK study. In Canada, where it's approved, they found that after the first dose,
it was 67 percent effective at preventing infection, and that in Scotland, after the second dose,
it was again 60 percent effective at preventing infection. Now what about hospitalization? Well in that UK
study, they found that it was 93 percent effective after the second dose, preventing hospitalization. In
the Canadian study that they looked at, it was 88 percent effective at preventing hospitalization and death,
if you took the Oxford-AstraZeneca vaccination. So again, very good numbers at preventing the worst
outcomes. Now what about the Johnson & Johnson vaccine? That's a one-time shot. What they found
is we don't have studies, currently, that look at the efficacy, but we do have some surrogates that
could be very informative. Now, the Johnson & Johnson vaccine was tested against the most strenuous
variant, or the worst variant at the time, back about six months ago, and that was the South
African variant, and when they tested the antibody response of the delta variant in comparison to the
South African variant, what it showed was that there was a higher level of antibody response
to the delta variant than there was even to the South African variant. In other words, a very
good antibody response to the delta variant. You may recall the South African variant with
respect to the Johnson & Johnson vaccine, there were no people who were hospitalized or died
of the South African variant 49 days after they received the Johnson & Johnson vaccine. In
fact, Johnson & Johnson put out a statement saying that as time went on, the immunity got
better up to even eight months after the Johnson & Johnson vaccination. So because these vaccinations
are so good at preventing hospitalization and death and also reasonable at preventing infection,
your risk from the delta variant is going to be predicated on a couple of things: number one, it's
going to be predicated on whether or not you're vaccinated. So it's also going to be predicated
on the amount of people in your area that are vaccinated. If there's a high frequency
of vaccination in the population around you, then you're going to be more protected and,
of course, the question also is how prevalent is the delta variant in your community as well?
So here's a nice article that actually looks at those key points, and if you look at this
map from the data that's available, you'll see here that the areas that are in light gray
are where there is 40 plus percent vaccinated or below case count threshold, and for those that
have the dark orange, as you can see here, this is where there is a low vaccination rate, less than 40 percent
and also an elevated case count. So this is where , if you are living in a county that is orange on
this map in the United States, that's where you might be concerned about the prevalence of the
delta variant in your community. And if you want more information, I highly recommend going to the
CDC covid data tracker, which gives you up-to-date information in your county and also your state.
I know this seems like a very small increase at this time; the purpose of this video is not
to scare you, but is to get you prepared as we get into the fall. There are a number of
factors that could be in play: there is a change in humidity; there is the change
in daylight hours; vitamin d production; being indoors versus outdoors. All of these may play
a role in the resurgence of a potential delta wave. I've gotten an increased amount of personal
phone calls from friends and family members who have told me that their loved ones have tested
positive for COVID, and i'm seeing it more often, and so all of the signs of another wave are coming.
And if you do get COVID, I highly recommend watching our video on "10 tips if you get COVID-19."
In this video, we go over in detail the types of things that you want to make sure that you are
doing to give yourself the best shot at surviving COVID-19. And as I go back to work, O really
don't want to see a repeat of what we had to witness in January and February of this year.
Since the vaccination campaign has started, I have not seen a single COVID-19 case in my intensive
care unit that had been vaccinated. All of the cases that I am seeing in the hospital
currently at this time are patients that did not get the COVID-19 vaccine. I'd like for all of you
out there to remain safe, get plenty of sleep, boost your immune system. Thanks for joining us.